Final answer:
Conference papers, research monographs, and encyclopedia entries are generally considered to be previews of works in progress.
Step-by-step explanation:
Conference papers are generally considered to be previews of works in progress and not final products like published journal articles. These papers are presented at conferences or symposiums and allow researchers to receive feedback and make improvements before publishing in a journal.
Research monographs are complete books or lengthy works that provide comprehensive and detailed analysis of a specific topic. They are often considered final products and are published after extensive research and review.
Encyclopedia entries are also generally considered to be previews of works in progress and not final products. They provide brief summaries and overviews of topics and are not typically considered strong sources for in-depth research.